Conveying mechanism, particularly applicable to classifiers



ULARLY APPLICABLE TO CLASSIFIERS April 27, 1937. R. STOKES CONVEYING MECHANI SM PART I C Filed March 21,1936 5 Sheets-Sheet 1 April 27, 1937. R. o. STOKES CONVEYING MECHANISM, PARTICULARLY APPLICABLE TO CLASSIFIERS Filed March 21, 1936 3 Sheets-Sheet 2 mm -m h .AIIIIHII .o\ N q. .o R w) 0 o :0 E o 0 x H. L \Qwmfi I a 5 Nmuw L J" I f \m N 1 m. u u. Q .6. mm m m a H m\ 1 a TF 0 i x mm Q Q 0 l etude P m Q o 6. N Q wm April 27, 1937. R, Q T KE 2,078,547

CONVEYING MECHANISM, PARTICULARLY APPLICABLE TO CLASSIFIERS Filed March 21, 1956 5 Sheets-Sheet 3 Patented Apr. 27, 1937 UNITED STATES CGNVEYING MECHANISM, PARTICULARLY APPLICABLE TO CLASSIFIERS Rupert- Octavius Stokes, London Wall, London,

England Application March 21, 1936, Serial No. 70,148 In Great Britain March- 28, 1935 6 Claims.

The invention relates to conveying mechanism, more particularly as applied to classifiers of the type in which the sediment in a liquid is moved up an inclined plane by rakes to be discharged over the upper edge, while the lighter particles remaining in suspension are discharged at some other place with the liquid.

Two sets of rakes with interlapping blades were proposed for conveying mechanism of this kind inthe specification of Patent No. 1,885,064, and

the present invention is directed to an arrangement for suspending and driving two sets of blades carrying out oppositely phased movements 4 in closed loops such as those just mentioned. The object of the invention is to provide simple mechanism by which the blades are moved in one direction while maintained as close as possible to the surface along which the material is a being moved. and. in the other direction at as smalla height above the other blades as is consistent with safety in operation. For instance it has been found possible with blades 4" high having a 12 longitudinal movement to ensure by means of, the invention satisfactory clearance between the blades with a. maximum rise of only 5", although a slightly larger clearance will usually be preferred.

According to the invention. two sets of rakes having. blades adapted. to be moved in one direction in close proximity to a conveying surface, and. in the opposite direction further from it, are. suspended from opposite ends of levers pivotally supported near their centres, and the levers are rocked. by cam. gear to raise and lower the rakes at the appropriate time in conjunction with means for reciprocating the rakes longitudinally.

Preferably the levers are parallel and similar as regards leading dimensions. Preferably also one lever only is driven by cam gear while the other lever or levers are driven from the first. For this purpose eachlever has an upward arm, and coupling bars between the arms ensure the similar movement of the levers.

It will be seen that the weight of the rakes is balanced, sothat driving power is economized. Ontheother hand there is no residual thrust in one direction to keep a cam follower in contact with a single cam of the-usual kind. The cam may therefore be made as a disc with a groove in its face. An arm on the lever would then be provided with a. roller engaging both sides of the cam groove in turn. Alternatively it is pos- ,sible to use two cams.

' The accompanying drawings show an embodiment of the invention and therein Figure 1 is an elevation of a classifier with interlapping blades, parts being broken away and the tank being in section.

Figure 2' is a plan of the same,

Figure 3 is a plan of the end part of the classiher and may be looked upon as a continuation of Figure 2 towards the right, and

Figure 4 is an end elevation taken in section on the line IV-IV of Figure 1'.

For convenience in drawing the inclined plane up which the sediment is conveyed has been taken as horizontal, the surface of the liquid in the tank I being indicated by the line 2 in' Figure 1.

The upper framework of the tank I supports a pair of pedestals 3, 3, in which a shaft 4 is journalled. The shaft is keyed to a rocker 5 of roughly rectangular shape with journal pins 6, 6, 1, l bolted on to project transversely from eachof its four corners. Four suspension rods 8, 8, 9, 9 are journalled on these pins. The rods 8, 8 are journalled at their lower ends to pins ID, ID attached-to a cross piece H which is connected to the longitudinal bars 25 supporting a set of rakes 21.

Similarly the rods 8, 9 are journalled to pins [2, 12 attached to a cross piece 23 which is connected to the longitudinal bars 26 supporting a set of rakes 28. The rakes 21 and 28 are so arranged that one set can pass along close to the inclined surface 29 forming here a part of the tank bottom, while the other set moves above them in the opposite direction.

The same framework also supports another pair of pedestals I3, 13 with a similar arrangement of shaft l4, rocker l5, pins l6, 16, H, I! and suspension rods l8, l8, l9, IS. The rods l8, I8 are journalled at their lower ends to pins 20 attached to a. cross piece 2i which is connected to the longitudinal bars 25 and with the cross piece it forms a complete support for the bars 25 and rakes 21.

Similarly the rods l9, l9 are journalled to pins 22, 22 attached to a cross piece 33 which is connected to the bars 26 and with the cross piece 23 forms a complete support for these bars and the rakes 28.

The rockers 5 and I5 are provided with similar arms 3!], 3i projecting upwards and connected by a link bar 32. It will be seen that the two sets of rakes are balanced one against the other through the two rockers and each set is constrained to move parallel to itself since the upward arms 30 and 3! are equal and parallel, the rockers 5 and I5 are equal and parallel and the suspension rods 8, 8, l8 and 18 are equal and parallel as also the suspension rods 9, 9, l9 and IS).

The mechanism just described controls the up and down movement ofthe rakes in the sense that an upward movement of one set is always counterbalanced by an equal and opposite downward movement of the other set and vice versa apart from any possible swing about the pins 6, I61 and 1, 11 respectively. A description will now be given of the mechanism for producing the longitudinal movement of the rakes.

A motor 34 mounted on a bracket on the tank drives a countershaft 35 by means of a pulley 36. A pinion 37 on the countershaft 35 meshes with the gear wheel 38 on a crank shaft 39. Two cranks 40 and 4| on the latter are set at 180 apart and are coupled by connecting rods 42 and 43 respectively to brackets 44 and 4-5. The bracket 44 is attached to one of the bars 25 and the bracket 45 to one of the bars 26. The longitudinal swing of the two sets of rakes 2! and 28 on the pins 6, 1, I6, ll will thus be in opposite phase.

For the purpose of raising and lowering the rakes at the appropriate times the crank shaft 39 is also equipped with two cams 46 and 41 of appropriate shape. The cam followers are rollers 48 and 49 carried on brackets 50 and 5| which are mounted on the under side of the rocker. I5. The rollers are disposed on opposite sides of the vertical plane through the axis of the shaft l 4 so that an upward thrust on one roller will tilt the rocker in one direction and keep the other roller close toits own cam. The cams 46 and 4'! are of course shaped to give the required sequence and extent of movements to the rakes in conjunction with the cranks 40 and 4|. Preferably the path of each rake is substantially a rectangle, the cams being then shaped to correct for the obliquity of the connecting rods 42 and 43. i

' What I claim is:

1. A reciprocating rake conveyor comprising in combination a supporting surface for the material being conveyed, two sets of rakes with interlapping blades, double-ended rocking lever members supporting the rakes and connected by one end of each to one of the said sets of rakes and by the other end of each to the other set, the arrangement being that in each of the two end positions of the said members one set of rakes is in proximity to the supporting surface and the other at a distance therefrom, means for oppositely reciprocating the two sets of rakes in the longitudinal direction of the supporting surface, and cam means for rapidly moving the rocking members over from one end position to the other while the rakes are near the end positions of their longitudinal movement.

2. A reciprocating rake conveyor comprising in combination a supporting surface for the material being conveyed, two sets of rakes with interlapping blades, double-ended rocking lever members supporting the rakes and connected by one end of each to one of the said sets of rakes and by the other end of each to the other set, the arrangement being that in each of the two end positions of the said members one set of rakes is in prox- 50 imity to the supporting surface and the other at a distance therefrom, a driving shaft, two cranks at 180 apart thereon, two connecting rods lying in an approximately longitudinal direction and each connected to one crank and one set of rakes, and

means for rapidly moving the rocking members over from one position to the other while the rakes are near the end positions of their longitudinal movement.

3. A reciprocating rake conveyor comprising in combination a supporting surface for the material being conveyed, two sets of rakes with interlapping blades, double-ended rocking lever members supporting the rakes and connected by one end of each to one of the said sets of rakes and by the other end of each to the other set, the arrangement being that in each of the two end positions 5 of the said members one set of rakes is in proximity to the supporting surface and the other at a distance therefrom, a driving shaft, two cranks at apart thereon, two connecting rods lying in an approximately longitudinal direction and 10 each connected to one crank and one set of rakes, and cam gear on the driving shaft for rapidly moving the rocking members over from one position to the other while the rakes are near the end positions of their longitudinal movement. 15

4. A reciprocating rake conveyor comprising in combination a supporting surface for the material being conveyed, two sets of rakes with interlapping blades, double-ended rocking lever members connected by one end of each to one of 20 the said sets of rakes and by the other end of each to the other set, the arrangement being that in each of the two end positions of the said members one set of rakes is in proximity to the supporting surface and the other at a distance 25 therefrom, a driving shaft, two cranks at 180 apart thereon, two connecting rods lying in an approximately longitudinal direction and each connected to one crank and one set of rakes, two cams on the driving shaft, and two cam follow- 30 ers on one of the rocking lever members on opposite sides of the pivot thereof and located to cooperate with the said cams.

5. A reciprocating rake conveyor comprising in combination a supporting surface for the ma- 35 terial being conveyed, two sets of rakes with in-. terlapping blades, two rocking lever members equal to each other in dimensions and centrally pivoted, equal upward arms on the said members, a coupling bar between the upper ends of 40 the said arms and equal in length to the distance between the pivots of the lever members, suspension rods of equal length on the ends of the lever members, those on similarly directed ends being connected to one set of rakes, means for 45 oppositely reciprocating the two sets of rakes in the longitudinal direction of the supporting surface, and means for rapidly moving the rocking members over from one end position to the other while the rakes are near the end positions of 50 their longitudinal movement.

6. A reciprocating rake conveyor comprising in combination a supporting surface for the material being conveyed, two sets. of rakes, two rocking lever members equal to each other in dimen- 'sions and centrally pivoted, equal upward arms on the said members, a coupling bar between the upper ends of the said arms and equal in length to the distance between the pivots of the lever members, suspension rods of equal length 60 on the ends of the lever members, those on similarly directed ends being connected to one set of rakes, a driving shaft, two cranks at 180 apart thereon, two connecting rods lying in an approximately longitudinal direction and each 65 connected to one crank and one set of rakes, two cams on the driving shaft, and two cam followers on one of the rocking lever members on opposite sides of the pivot thereof and located to cooperate with the said cams. 7

RUPERT OCTAVIUS STOKES. 

